Method and apparatus for examining liquid filled containers

ABSTRACT

A container which is at least partially filled with a liquid is centrifuged while its longitudinal axis is maintained substantially perpendicular to its axis of rotation thereby causing impurities which may be present in the liquid to move to the end of the container farthest from the axis of rotation while the air bubbles in the liquid collect at the end of the container nearest to the axis of rotation. The container is then moved diametrically past the axis of rotation causing the air to move to the opposite end of the container. The centrifuging of the container continues causing any impurities which may be present to be transferred from the end of the container in which they have been collected to the opposite end. The presence or absence of these impurities is sensed by a photoelectric device during this transfer.

United States Patent Hansen et a1.

METHOD AND APPARATUS FOR EXAMINING LIQUID FILLED CONTAINERS Knut BondeHansen, Malmo; John Soren Petersson, Sodertalje, both of SwedenAssignee: Aktlebolaget Astra, Sodertalje, Sweden Filed: June 11, 1969Appl. No.: 832,187

Inventors:

References Cited UNITED STATES PATENTS 7/1951 Hewson ..23/253 us]3,659,940 51 May 2,1972

Primary Examiner-Ronald L. Wibert Assistant Examiner-Warren A. SklarAttorney-Brumhaugh, Graves, Donohue & Raymond [57] ABSTRACT A containerwhich is at least partially filled with a liquid is centrifuged whileits longitudinal axis is maintained substantially perpendicular to itsaxis of rotation thereby causing impurities which may be present in theliquid to move to the end of the container farthest from the axis ofrotation while the air bubbles in the liquid collect at the end of thecontainer nearest to the axis of rotation. The container is then moveddiametrically past the axis of rotation causing the air to move to theopposite end of the container. The centrifuging of the containercontinues causing any impurities which may be present to be transferredfrom the end of the container in which they have been collected to theopposite end. The presence or absence of these impurities is sensed by aphotoelectric device during this transfer.

11 Claims, 11 Drawing Figures Patented May 2, 1972 3,659,940

4 Sheets-Shoat 1 INVENTORS. KNUT BONDE HANSEN 8 J HN SOREN ETERSSON B Ytheir ATT R/VEYS.

Patented May 2, 1972 4 Sheets-Sheet 5 lllilllllilllil INVENTORS.

m mw R m m AE E HP E om g m Wm r as A M .w NW m KJ Patented May 2, 19724 Shoots-Sheet 4 INVENTORS. KNUT BONDE HANSEN & JOHN SQREN ETERSSON WM[9 their ATT RNEYS.

METHOD AND APPARATUS FOR EXAMINING LIQUID FILLED CONTAINERS BACKGROUNDOF THE INVENTION The present invention relates to a method and apparatusfor examining a container to determine the absence or presence ofimpurities, and more particularly to a novel and highly effective methodand apparatus for determining the presence of these impurities bycentrifuging the container while it is held in two successive positions.

A difficult problem is presented by the need to determine whethercontainers which have been filled with a liquid are contaminated byimpurities which may have been introduced into the container when theywere filled or closed. It has not been found possible to completelyeliminate the occurrence of these impurities despite the maintenance ofhigh standards of cleanliness when the containers are washed, filled,and closed. Moreover, impurities may be present in the liquid which aretraceable to the manufacture and treatment of the liquid itself and,therefore, not easily excluded during the filling and closing of thecontainers.

The problem described is of particular importance when, for example,ampoules are filled with and injection solution. It has been found thatfibers, glass fragments, and the like are occasionally present in thefilled ampoules despite efiorts to guard against this contamination.

Because containers do contain impurities, it is necessary to provide amethod and apparatus for examining the containers and segregating thosewhich are contaminated by impurities. One known procedure is to manuallyexamine ampoules under a strong light. This, however, is expensive andtime consummg.

It is also known to examine ampoules to determine whether impurities arepresent by utilizing photoelectric devices. One known device causes alight source to be projected onto a concaved mirror and through acondensing lens and diaphragm. The beam thus produced is used to lightan electrical screen utilizing an optic edge and an achromatic lens. Theampoule to be examined is disposed in front of the concaved mirror androtated. When the rotation is stopped abruptly any particles ofimpurities which are present in the liquid continue to move because ofinertial force. Spots caused by the particles are registered on thescreen. Ampoules containing particles of impurities can be identifiedand discarded in this way. It has been discovered however, by manualexamination, that a large portion of the discarded arnpoules are, infact, free from contamination. This is because the ampoules containsmall air bubbles which move through the liquid and are registered onthe lighted electrical screen in the same manner as particles ofimpurities. It has not previously been possible, despite ingenious andsensitive examining devices, to distinguish between the air bubbles andthe contaminating particles.

SUMMARY OF THE INVENTION The invention provides a novel and highlyeffective solution to the problem described above. According to theinvention, a container, which is at least partially filled with aliquid, is centrifuged by causing it to move along a circular path aboutan axis of rotation while maintaining the longitudinal axis of thecontainer substantially perpendicular to the axis of rotation. Afterbeing centrifuged for an appropriate time and at a sufiicient speed inthis position, the container is caused to move diametrically toward theopposite periphery of the circular path, thereby causing the interior ofthe container to move past the axis of rotation. The centrifuging of thecontainer then continues while the longitudinal axis is again maintainedsubstantially perpendicular to the axis of rotation. While the containeris being centrifuged, but before it has been moved diametrically, theimpurities which may be present in the container will be collected atthe end of the container which is farthest from the axis of rotation.During this continued centrifuging the container is examined todetermine the absence or presence of impurities. Air which may bepresent in the container will move to the end of the container which isthen closest to the axis of rotation. The air may collect in the form ofone large bubble. After the container has been moved diametrically, andwhile the centrifuging is continued, the impurities which may be presentin the liquid will be transferred to the end of the container which isthen farthest from the axis of rotation. It is during this movement ofthe impurities that the presence or absence of impurities isphotoelectrically detected.

The means for examining the container may be mounted so as to bediametrically displaceable. In this case the container may be examinedafter its interior has moved past the axis of rotation. Alternatively,the means for examining the container may be mounted so as to bestationary with respect to its diametrical position. In this case thecontainer is examined as it moved diametrically past the means forexamining it.

An apparatus for carrying out the method described above may comprise arotatable platform which may be horizontally disposed so as to form thebase plate of a rotatable housing. Holding means for maintaining thecontainer in the desired orientation and a means for examining thecontainer which may be mounted on the base plate may be fixedlyconnected to a vertical, rotatably mounted first shaft means which isprovided with an opening passing longitudinally through its center. Theholding means may comprise a holding tube which is mounted so as to berotatable between a vertical and a horizontal orientation within thehousing. The holding tube, when in its vertical position, may be inalignment with the opening in the first shaft means. The holding tubemay be fixedly connected to a first shaft means at a distance from thebase plate and may thereby be rotated between its vertical andhorizontal orientation.

A means for feeding the containers to be examined is stationarilydisposed above the center of the housing. It comprises a centering tubeand a means for controlling the movement of the containers into theholding means.

The invention provides a method and apparatus for examining liquidfilled containers in a highly reliable manner whereby those containerscontaminated by impurities can be segregated. An essential factor isthat air bubbles which may be present in the container are notregistered during the examination of a container.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding ofthe invention, reference may be had to the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIGS. 1 3 are diagrammatic representations showing a container duringstages of an examination carried out in accordance with the method ofthe invention;

FIG. 4 is an orthographic projection in section of an apparatusconstructed in accordance with the invention;

FIG. 5 is a sectional pictorial representation of the apparatus of FIG.4; and

FIGS. 6 11 are modified diagrammatic representations showing a portionof the apparatus of FIGS. 4 and 5 during various phases of its operatingcycle.

DESCRIPTION OF THE PREFERRED EMBODIMENT The principles of the method ofthe invention will be described first. FIGS. 1 3 show a container 1which comprises a cylindrical arnpoule and is at least partially filledwith a liquid. The liquid may be an injection solution. The container lis disposed with its longitudinal axis 2 perpendicular to and at asuitable distance from and axis of rotation 3. The container 1 issubjected to centrifuging by causing it to move along a circular path 4while maintaining the longitudinal axis 2 of the container 1substantially perpendicular to the axis of rotation 3. Air may bepresent in the container 1 in the form of a bubble 5. Impurities 6 mayalso be present in the container 1. These impurities may, for example,be glass fragments, small pieces of dirt, or fibers.

The container 1 is centrifuged at a speed sufiicient to cause theimpurities 6 which may be present to be collected at the end of thecontainer 1 which is farthest from the axis of rotation 3, this speedalso being sulficient to cause the air which may be present in thecontainer 1 to move to the end of the container 1 nearest to the axis ofrotation 3.

A means for examining the container to determine the absence or presenceof impurities with which it is at least partially filled, shown here asexamination station 7, is disposed in the plane of the circular path 4.After the air bubble 5 and the particles 6 have been caused, by thecentrifuging of the container l, to move to their respective positionsdescribed above, the container 1 is caused to move diametrically pastthe axis of rotation 3 toward the opposite periphery of the circularpath 4. As shown in the drawings, the container 1 moves from theposition shown in FIG. 1, through the position shown in FIG. 2, to theposition shown in FIG. 3. This diametrical movement of the container 1takes place during continuous centrifugation by rotation about the axisof rotation 3. As the container 1 passes the axis of rotation 3 the airbubble 5 remains over the axis at the point 8. Thus as the container 1continues its diametrical movement, the air bubble 5 is transferred tothe opposite end of the container 1 which is then nearest to the axis ofrotation 3.

The container 1 continues to be centrifuged, after it has been moveddiametrically at a speed sufficient to cause the impurities 6 which maybe present to be transferred to the end of the container 1 which is thenfarthest from the axis of rotation 3. The container 1 is examined duringthis transfer of the impurities which move through one or more beams oflight and their presence is detected by one or more photoelectric cellswhich generate electrical signals.

The longitudinal axis 2 of the container I, referred to above, isconsidered to be an imaginary line which passes through the container 1and the axis of rotation 3 while the container 1 is held in the positionin which it is centrifuged. In the instance of a particular containerthis axis is preferably selected to provide the most effectivecollection of the impurities and to provide the most effective detectionof the impurities after the container has begun to move diametrically.

The container 1 may be fed to the examining apparatus with itslongitudinal axis 2 substantially coincident with the axis of rotation3, in which case the container 1 is rotated into a position in which itis perpendicular to the axis of rotation 3 before it is centrifuged.Alternatively, the container 1 may be fed to the examining apparatuswith its longitudinal axis 2 substantially perpendicular to the axis ofrotation 3. In this case it may be fed at the periphery of the circularpath 4.

An apparatus for carrying out the method described above is shown inFIGS. 4 and 5 and will now be described. A cylindrical housing 9 and arotatably mounted platform 10 are provided. The rotatably mountedplatform 10 comprises a horizontally disposed circular disc which formsthe base plate of the housing 9. The platform 10 is attached to avertically disposed rotatably and concentrically mounted first shaftmeans 1 1.

The first shaft means 11 is engaged by a cylindrical casing 12, which isrotatably mounted in a bearing housing 13. The bearing housing 13 isprovided, on its lower extension, with a pully l4 driven by a flexiblebelt 15 which is partially conical in cross section. The bearing housing13 is mounted on a supporting member 16.

The first shaft means 1 1 is fixidly attached to the cylindrical casing12 by means of a locking nut 17 which is engaged by threads on a lowerportion of the casing 12. The vertically mounted first shaft means 11 isprovided with a cylindrical opening 18 which passes longitudinallythrough its center and has a diameter somewhat greater than the diameterof the containers which the apparatus is used to examine.

The first shaft means 11 is further provided with a channel 19 (see FIG.4) which is connected to a compressed air tube 20 by a peripheralopening 21 which circumscribes the first shaft means 1 1. Thus, an openpath is maintained between the compressed air tube 20 and the channel 19during the rotation of the first shaft means 11. The compressed air fromchannel 19 passes through a hole in the platform 10 to a conduit (notshown) having three branches and located within the cylindrical housing9. Each branch of the conduit is provided with a valve (not shown). Twoof the branches of the conduit are connected to compressed air cylinders22 and 23 respectively (note FIG. 5). A third branch 24 of the conduitis disposed within the partition 25 and ends in an opening 26 disposedat a distance from the platform 10. The opening 26 is directed towardthe center of the housing 9. Partition 25 has a fixed orientation withinthe housing 9 and is provided with two apertures 27 and 28, each havinga shape of a sector of a circle.

A holding means, comprising holding tube 34, for maintaining thelongitudinal axis of the container substantially perpendicular to theaxis of the platform 10 is provided. To support and actuate this holdingmeans bearings 29 and 30 are vertically disposed on opposite sides ofthe partition 25 (see FIG. 5) to engage a second shaft means 31 which isconnected to the holding means and is disposed at a distance from thebase plate 10 and perpendicular to the partition 25. The second shaftmeans 31 has portions which project into the bearings 29 and 30. A rack32 engages a gear wheel 33 which is attached to the portion of secondshaft means 31 which projects into the bearing 29. The rack 32 isarranged to be actuated by the compressed air cylinder 23 and therebycause rotation of the second shaft means 31.

The holding means, comprising the holding tube 34, is arranged to berotatable between a vertical and a horizontal orientation by the secondshaft means 31 which is provided with a hole concentric with one of itsdiameters and located at its intersection with the holding tube 34. Theholding tube 34 has an inside diameter somewhat larger than the diameterof the containers which are to be examined. The second shaft means 31 isarranged to be rotated by the rack 32 and the gear wheel 33 therebyrotating the holding tube 34 from its vertical to its horizontalorientation.

The holding tube 34 is of a length such that it lies in close proximityto a curved interior edge 35 of the partition 25 formed by the aperture27. The corner of the aperture 27 opposite the curved edge 35 iscoincident with the intersection of the second shafl means 31 and theholding tube 34. whensthe holding tube 34 is rotated into its horizontalorientation it will abut against or move close to an edge of theaperture 27 on which a resilient damping means, comprising a pad 36, isprovided. A similar resilient damping means, comprising pad 37, isprovided on another edge of aperture 27 so as to engage the holding tube34 when it moves to its vertical orientation.

A means 38 for examining the container to determine the absence orpresence of impurities in the liquid with which it is at least partiallyfilled is fixedly attached to the partition 25 next to the aperture 27.The means 38 for examining containers comprises a low resistancephotoelectric element of, for example, silicium or cadmium sulphide. Thephotoelectric element is illuminated through an optical lens (not shown)and a vertical slit 39, by a lamp (not shown). The components of themeans 38 for examining containers are arranged so that the light beam isdirected substantially perpendicular to an extension of the center lineof the holding tube 34 when it is at its horizontal orientation, withits longitudinal axis substantially perpendicular to the axis ofrotation of the platform 10.

The compressed air tube 22 has provided therewith a first blocking means40 disposed between the upper part of first shaft means 1 l and thelower part of the holding tube 34. The first blocking means 40 has aresilient upper surface which functions as a damping means. It isarranged to be actuated by the compressed air cylinder 22 whereby it canbe withdrawn at the appropriate time during each operating cycle of theapparatus, thus providing an unobstructed path formed by the holdingtube 34 and the opening 18 of the first shaft means 1 1. The firstblocking means 40 is subsequently returned to its original position,obstructing this path, by means of a spring (not shown) located in thehousing of the compressed air cylinder 22.

A means for feeding the containers to be examined is stationarilydisposed above the center of housing 9. It comprises a centering tube 41and an electromagnetic means 42 for controlling the movement of thecontainers into the holding means comprising holding tube 34.Electromagnetic means 42 is arranged to operate a second blocking means43, which is withdrawn when it is desired to release an ampoule 44 intothe centering tube 41. The centering tube 41 is arranged so that thelongitudinal axis of the ampoule 44 will be aligned with the centers ofthe holding tube 34 and the first shaft means 11. In addition, thecentering tube 41 may serve as a means for checking the diameters ofcontainers whereby ampoules which are too large in diameter areprevented from passing through the centering tube 41 into the means forholding the containers, comprising holding tube 34.

Arranged beneath the first shaft means 11 is a rotatably mounted guidemeans 45 which is rotatably mounted at a point located outside andextension of the walls of the opening 18 provided in the first shaftmeans 11. Movement of the guide means 45 is controlled by anelectromagnetic means 46 which is supported by a shank 47.

As can be seen in FIG. 4, the underside of the platform is provided withcircular contact paths 48. Sliding contacts 49 are arranged to lieadjacent these circular contact paths 48 during the rotation of thecylindrical housing 9. This provides the components mounted on andwithin the housing 9 with electrical power and provides a path forelectrical signals which control electromagnetic means 42 and 46. Theabove described circuit means similarly controls the valves associatedwith the two branches of the conduits which supply compressed aircylinders 22 and 23. The circuit means also controls the valveassociated with the branch 24 of the conduit which provides a stream ofcompressed air emitted from opening 26. A photoelectric cell (not shown)is provided as a means for sensing the completion of an operating cyclewhich is indicated by the fall of an examined ampoule from the lower endof opening 18.

The operation of the apparatus shown in FIGS. 4 and 5, which takes placein accordance with the method of the invention, will now be described.The belt supplies power to a pully 14 thereby causing the first shaftmeans 11 and the cylindrical housing 9 to rotate at a speed ofapproximately 300 revolutions per minute, which is suitable for causingthe desired movement of impurities and air, which may be present in thecontainer. An operating cycle commences when an electrical impulseactuates the electromagnetic means 42 thereby causing it to withdraw thesecond blocking means 43 and allowing the ampoule 44 to move downwardunder the force of gravity into the centering tube 41. The blockingmeans 43 then returns to the position shown in the drawings. The ampoule44 descends from the centering tube 41 into the holding tube 34 whichis, at this time, vertically oriented. The descending ampoule 44 isintercepted by the resilient surface of the first blocking means 40. Thesharp impact of the ampoule 44 is softened by its resilient surface.

FIGS. 6 through 1] illustrate positions of the ampoules and apparatusduring various phases of the examining procedure. In these Figures theelectrically controlled compressed air cylinder 22 has been displaced 90so as to give a clear and unobstructed view of the operation.

After the ampoule 44 has attained the position illustrated in FIG. 6,the valve associated with the branch of the conduit connected to thecompressed air cylinder 22 receives an electrical signal which resultsin the rack 32 being displaced by the force of the compressed air. Thesecond shaft means 31 is thus rotated causing the holding tube 34 whichholds the ampoule 44 to rotate approximately 90 to its horizontalorientation, as shown in FIG. 7. As the holding tube 34 moves from itsvertical to its horizontal orientation the ampoule 44 is pressed, bycentrifucal force, against the curved edge 35 of the partition 25. Theampoule 44 then continues to be centrifuged in the position illustratedin FIG. 7 in which the holding means comprising the holding tube 34maintains the longitudinal axis of the container substantiallyperpendicular to the axis of rotation of the platfonn l0, i.e., thecenter of first shafi means 11. Thus, the rotation of the cylindricalhousing 9 causes impurities such as glass fragments, fibers, and thelike, which may be 44, to be collected at the end of the ampoule 44which is farthest from the axis of rotation of the platform 10 andclosest to the periphery of the circular path about the axis along whichthe container is rotated. A second effect of the centrifugation is tocause the air which may be present in the ampoule 44 to from a single,large bubble at the end of the ampoule 44 which is closest to the axisof rotation of platform 10.

The movement of the impurities to the end of the ampoule 44 farthestfrom the axis of rotation of platform 10 is attributable largely to thecentrifugation while the ampoule 44 is in its horizontal orientationillustrated in FIG. 7. However, this collection of impurities is alsopartially attributable to the tendency of these impurities to move tothat end of the ampoule 44 when it comes to an abrupt stop against theresilient surface of the first blocking means 40.

After the ampoule 44 has been centrifuged in its horizontal position fora number of seconds, the valve associated with the branch 24 of thecompressed air conduit is opened thereby causing a horizontally directedstream of compressed air to be emitted from the opening 26 into theholding tube 34. Thus. the ampoule 44 is caused to move from theposition shown in FIG. 7 to the position shown in FIG. 8, in which it isin close proximity to the light emitting vertical slit 39. The ampoule44 comes to a stop against a damping means 50. As can be seen in FIG. 8a large portion of the ampoule 44 is then situated outside of theholding tube 34 between the light source and the photoelectric elementof the means 38 for examining the container. Its longitudinal axiscontinues to be maintained substantially perpendicular to its axis ofrotation. The center of the ampoule 44 is substantially situatedadjacent the vertical light emitting slit 39.

s explained above, the air bubbles in the ampoule 44 will remain at thecenter of rotation over the center of the second shaft means 31 as theampoule 44 moves diametrically past this point. After the interior ofthe ampoule 44 has moved passed the axis of rotation, the air bubble,thus has moved the entire length of the ampoule 44 and is situated atthe opposite end which is now closest to the axis of rotation, thisbeing the same end of the ampoule 44 at which the impurities are nowgathered.

As the ampoule 44 moves to the position illustrated in FIG. 8 the beamof light emitted by the slit 39 is interrupted by a metal envelopeprovided on the end of the ampoule 44. This causes the photoelectricelement of the means 38 for examining the containers to produce a sharpelectrical impulse. In the event that the ampoule 44 is inserted in theapparatus in the reverse position, the function of the metal envelope isfulfilled by a rubber stopper which closes the opposite end of theampoule 44. The impulse thus generated by the means 38 for examining thecontainers causes the photoelectric examination of the ampoule 44 tocommence. passes the light emitting slit 39 through its liquid contents.

As the ampoule 44 continues its diarnetrical movement it moves past thelight emitting vertical slit 39 enabling successive portions of theampoule 44 to be examined. Accordingly, the impurities which are at thistime transferred through the ampoule 44 toward the end which is nowfarthest from the axis of rotation, because of the centrifuging of theampoule 44, will pass through the beam of light causing variations inthe electrical signal generated. If impurities are present in theampoule 44, the varying electrical signal causes the guide plate 45 tomove from its vertical first position (shown in FIG. 10) to an angulatedsecond position (shown in FIG. 11). The guide plate 45 thus divertscontaminated ampoules from the path they would otherwise take, causingthem to fall into a segregated group.

After the examination of each ampoule is completed the guide plate 45returns to its vertical position so that the next arnpoule, if it doesnot contain impurities, will be pemiitted to fall without striking theguide plate 45. In the instance in which the ampoule does not containimpurities a variable electrical signal, which indicates the presence ofimpurities, is not generated and the guide plate 45 remains in itsvertical position as shown in FIG. 10.

When an ampoule which has been examined passes through the first shaftmeans 11 it is sensed by photoelectric cell located between the lowerend of the shaft and the guide plate 45. This photoelectric cellgenerates a signal which actuates electromagnetic means 42 therebycausing the next ampoule to be fed to the apparatus commencing the nextoperating cycle. If, at the conclusion of an operating cycle, an ampouleis not sensed by the photoelectric cell beneath first shaft means 11,this is an indication that the ampoule has become lodged in theapparatus, probably in the centering tube 41, and a signal isaccordingly generated which stops the rotation of the cylindricalhousing 9. Ampoules become stuck in the apparatus primarily becausetheir diameters are too large. Accordingly, it is possible to preventsuch stoppages of the apparatus by checking the diameters of theampoules in a separate device before they are delivered to the centeringtube 41.

It will be obvious to those skilled in the art that the above describedembodiment is meant to be merely exemplary and that it is susceptible ofmodification and variation without departing from the spirit and scopeof the invention. For example, one or more photoelectric elements may bedisposed so that two light streams may be caused to pass through thecontainers, perpendicular to each other. The containers, which are atleast partially filled with liquid, may be breakarnpoules, cylindricalampoules, small injection flasks, (conveniently having a volume of up toapproximately 20 milliliters) or other similar containers. Therefore,the invention is not deemed to be limited except as defined by theappended claims.

We claim:

1. An apparatus for examining a container which has a longitudinal axisand is at least partially filled with a liquid, comprising a rotatablymounted platform, a holding means for maintaining the longitudinal axisof the container substantially perpendicular to the axis of rotation ofsaid rotatable platform, means for causing said container to move withinsaid holding means past the axis of rotation of said platform toward theopposite side of said platform, and means for examining the container todetermine the absence or presence of impurities in the liquid with whichit is at least partially filled while the longitudinal axis of thecontainer continues to be maintained by said holding means substantiallyperpendicular to the axis of rotation of said platform.

2. The apparatus of claim 1, wherein a means for feeding the containersto be examined is stationarily disposed above the center of saidplatform, said means for feeding the containers comprising a centeringtube and a means for controlling the movement of the containers into theholding means.

3. The apparatus of claim 1 further comprising a vertically disposedrotatably mounted first shaft means which is provided with an openingthat passes longitudinally through its center, wherein said rotatablymounted platform comprises a horizontally disposed circular disc, saidplatform being attached to said first shaft means, said holding meanscompris ing a holding tube which is rotatable into a vertical positionin which it is in alignment with the opening in said first shaft means.

4. The apparatus of claim 1 further comprising a second shaft means towhich said holding means is connected whereby said first shafi means canbe rotated, said holding means comprising a holding tube which isarranged to be rotatable between a vertical and a horizontalorientation.

5. The apparatus according to claim 1 wherein the means for examiningthe container includes a light source and a photocell.

6. The apparatus of claim 4, wherein said means for examining thecontainer is disposed at a distance from said platform and is alignedwith the position of said holding tube when said holding tube assumesits horizontal orientation.

7. A method of determining whether impurities are present in a containerwhich is at least partially filled with a liquid comprising the stepsof:

centrifuging the container by moving it along a circular path about anaxis of rotation, moving the container diametrically across its circularpath, thereby causing the interior of the container to move past theaxis of rotation and causing any impurities present in the container tochange position within the container; and

examining the container while it is being centrifuged by directingradiant energy at the container and detecting the energy which passestherethrough, whereby the presence or the absence of impurities withinthe container is determined.

8. The method of claim 7 wherein the step of centrifuging the containeris carried out at a speed of rotation sufiicient to cause impuritieswhich may be present in the container to be collected at the end of thecontainer which is farthest from the axis of rotation, this speed alsobeing sufficient to cause any air which may be present in the containerto move to the end of the container nearest to the axis of rotation, andwherein the container continues to be centrifuged after it has beenmoved diametrically at a speed suflicient to cause the impurities whichmay be present to be transferred to the end of the container which isthen farthest from the axis of rotation, and wherein the step ofdirecting radiant energy at the container is carried out during thistransfer of the impurities.

9. The method of claim 7 wherein the container is examined after theinterior of the container has moved diametrically past the axis ofrotation, wherein the radiant energy is directed at the container bymeans for examining the container, and wherein the means for examiningthe container is moved with respect to the axis of rotation while thecontainer is examined.

10. The method of claim 7 wherein the container is examined by anapparatus that remains stationary with respect to the axis of rotationwhile the container is examined.

11. The method of claim 7 further comprising first feeding the containerwhich has a longitudinal axis into an examining apparatus in a positionin which its longitudinal axis is substantially coincident with the axisof rotation, and then rotating the container into a position in whichits longitudinal axis is substantially perpendicular to the axis ofrotation.

1 i i i i

1. An apparatus for examining a container which has a longitudinal axisand is at least partially filled with a liquid, comprising a rotatablymounted platform, a holding means for maintaining the longitudinal axisof the container substantially perpendicular to the axis of rotation ofsaid rotatable platform, means for causing said container to move withinsaid holding means past the axis of rotation of said platform toward theopposite side of said platform, and means for examining the container todetermine the absence or presence of impurities in the liquid with whichit is at least partially filled while the longitudinal axis of thecontainer continues to be maintained by said holding means substantiallyperpendicular to the axis of rotation of said platform.
 2. The apparatusof claim 1, wherein a means for feeding the containers to be examined isstationarily disposed above the center of said platform, said means forfeeding the containers comprising a centering tube and a means forcontrolling the movement of the containers into the holding means. 3.The apparatus of claim 1 further comprising a vertically disposedrotatably mounted first shaft means which is provided with an openingthat passes longitudinally through its center, wherein said rotatablymounted platform comprises a horizontally disposed circular disc, saidplatform being attached to said first shaft means, said holding meanscomprising a holding tube which is rotatable into a vertical position inwhich it is in alignment with the opening in said first shaft means. 4.The apparatus of claim 1 further comprising a second shaft means towhich said holding means is connected whereby said first shaft means canbe rotated, said holding means comprising a holding tube which isarranged to be rotatable between a vertical and a horizontalorientation.
 5. The apparatus according to claim 1 wherein the means forexamining the container includes a light source and a photocell.
 6. Theapparatus of claim 4, wherein said means for examining the container isdisposed at a distance from said platform and is aligned with theposition of said holding tube when said holding tube assumes itshorizontal orientation.
 7. A method of determining whether impuritiesare present in a container which is at least partially filled with aliquid comprising the steps of: centrifuging the container by moving italong a circular path about an axis of rotation, moving the containerdiametrically across its circular path, thereby causing the interior ofthe container to move past the axis of rotation and causing anyimpurities present in the container to change position within thecontainer; and examining the container while it is being centrifuged bydirecting radiant energy at the container and detecting the energy whichpasses therethrough, whereby the presence or the absence of impuritIeswithin the container is determined.
 8. The method of claim 7 wherein thestep of centrifuging the container is carried out at a speed of rotationsufficient to cause impurities which may be present in the container tobe collected at the end of the container which is farthest from the axisof rotation, this speed also being sufficient to cause any air which maybe present in the container to move to the end of the container nearestto the axis of rotation, and wherein the container continues to becentrifuged after it has been moved diametrically at a speed sufficientto cause the impurities which may be present to be transferred to theend of the container which is then farthest from the axis of rotation,and wherein the step of directing radiant energy at the container iscarried out during this transfer of the impurities.
 9. The method ofclaim 7 wherein the container is examined after the interior of thecontainer has moved diametrically past the axis of rotation, wherein theradiant energy is directed at the container by means for examining thecontainer, and wherein the means for examining the container is movedwith respect to the axis of rotation while the container is examined.10. The method of claim 7 wherein the container is examined by anapparatus that remains stationary with respect to the axis of rotationwhile the container is examined.
 11. The method of claim 7 furthercomprising first feeding the container which has a longitudinal axisinto an examining apparatus in a position in which its longitudinal axisis substantially coincident with the axis of rotation, and then rotatingthe container into a position in which its longitudinal axis issubstantially perpendicular to the axis of rotation.